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std::启动服务器时发生异常(WinSock2)

winsock2 visual-c++ c++

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000000000000000000000 · 技术社区 · 10 年前

我是C++新手,目前正在从 tutorial 如何使用winsock(2)。
然而,我的服务器遇到了问题。我不知道这是怎么发生的。

#include "stdafx.h"
#include <WinSock2.h>
#include <winsock.h>

#pragma comment(lib, "Ws2_32.lib")

using namespace std;

void cmdError(string e = ""){
    cout << "Error:\n" << e << endl;
    chrono::milliseconds t( 3000 );
    this_thread::sleep_for( t );
}

void startServer(int port){
    SOCKET acceptSocket;
    SOCKET connectedSocket;
    SOCKADDR_IN addr;
    addr.sin_family=AF_INET;
    addr.sin_port=htons(port);
    addr.sin_addr.s_addr=ADDR_ANY;
    memset(&addr, 0, sizeof(SOCKADDR_IN));
    long rc;
    acceptSocket = socket(AF_INET, SOCK_STREAM, 0);
    if(acceptSocket = INVALID_SOCKET){ throw new exception();}
    rc = ::bind(acceptSocket, (SOCKADDR*) &addr, sizeof(SOCKADDR_IN));
    if(rc == SOCKET_ERROR){ throw new exception();}
    rc = listen(acceptSocket, 10);
    if(rc == SOCKET_ERROR){ throw new exception();}
    connectedSocket = accept(acceptSocket, NULL, NULL);
    if(connectedSocket == INVALID_SOCKET){ throw new exception();}
}

void startClient(string ip, int port){
    long rc;
    SOCKADDR_IN addr;
    SOCKET s = socket(AF_INET, SOCK_STREAM, 0);
    if(s == INVALID_SOCKET){ throw new exception();}

    memset(&addr, 0, sizeof(SOCKADDR_IN));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);
    addr.sin_addr.s_addr = inet_addr(ip.c_str());
    rc = connect(s, (SOCKADDR*)&addr, sizeof(SOCKADDR));

    if(s == SOCKET_ERROR){ throw new exception();}
}

int _tmain(int argc, _TCHAR* argv[]){
    WSADATA wsa;
    if(WSAStartup(MAKEWORD(2, 0), &wsa) != 0){
        cmdError();
        return 1;
    }
    string n;
    int port;
    cout << "Please specify the task of this thread. \nEnter 'server' or 'client'." << endl;
    getline(cin, n);
    system("cls");
    cout << "Please specify a port." << endl;
    cin.clear();
    cin.sync();
    cin >> port;
    system("cls");
    if(n.at(0) == 'c' || n.at(0) == 'C'){
        string ip;
        cout << "You started a client application." << endl;
        cout << "Enter the IP address of the server you want to connect to." << endl;
        cin.clear();
        cin.sync();
        getline(cin, ip);
        system("cls");
        cmdError();
        try{
            startClient(ip, port);
        }
        catch(exception e){
            cmdError();
            e.~exception();
            return 1;
        }

        return 0;
    }
    else if(n.at(0) == 's' || n.at(0) == 'S'){
        cout << "You started a server application" << endl;
        try {
            startServer(port);
        }
        catch(exception e){
            e.~exception();
            return 1;
        }
        return 0;
    }
    cmdError();
    return 1;
}

void sendStr(string msg){
}

当我通过应用程序启动服务器时 void startServer(int port) .

First-chance exception at 0x7667C42D in test.exe: Microsoft C++ exception:
std::exception at memory location 0x001EF5C8.

If there is a handler for this exception, the progrram may be safely continued.

知道为什么会这样吗?

1 回复 | 直到 10 年前

1

Community CDub 8 年前

你没有接住你扔的东西。你在扔一个 exception * 你想抓住一个 exception .

你几乎不应该扔 new 异常,您应该只抛出一个异常,然后应该捕获对所述异常的常量引用,例如:

#include <exception>
#include <iostream>

int
x(int y)
{
    throw std::exception();
}

int
main(int argc, char **argv)
{
    try {
        x(2);
    } catch (const std::exception &e) {
        std::cout << "Oops" << std::endl;
    }
    return 0;
}

如果我使用了你的代码,我会因为一个未捕获的异常类型而终止程序 std::exception * (注意,它是指向 std::exception ,不是 std::异常 .

此外,我不知道你想用 e.~exception(); 。它在该代码中没有位置。如果您试图删除您的异常 新 d、那么你应该 delete 像这样对析构函数的显式调用表明您很难理解对象生命周期;这是 C++ 语言

查尔斯·贝利的 answer to this question 也会详细说明为什么会这样。